The present disclosure relates to the field of lighting, and more particularly to luminaires employing light emitting diodes (LEDs), and methods of controlling such LED-based luminaires.
LED-based luminaires have been gaining increased acceptance as the efficiency and long-life of LEDs becomes better known. However, LEDs behave differently than many other types of light source. For example, in contrast to traditional incandescent lamps, which emit light generally around 360° from the light source, LEDs typically are provided in “packages” that include a focusing element that directs light over a limited direction range, such as 120°. Also, LED-based luminaires typically include several individual LED packages mounted on a circuit board. The physical aspects and behavior of LED packages create new challenges for some lighting applications.
The long-life benefits of LEDs are best cu aced by controlling the heat to which LEDs are exposed, as excessive heat can decrease the brightness and working life of LEDs. Thus, LED-based luminaires often have heat management structures that evacuate heat from the LEDs in order to maintain the heat within a desired range. However, LED-based luminaires may be used in a wide range of applications and environments. Some heat management structures may not be sufficient to maintain the LEDs within a desired range of heat if the surrounding environment is too warm, or if other factors decrease the efficacy of the heat management structure.